It is well known in the prior art that certain benezimidazole derivatives have substantial anthelmintic activity in sheep, cattle, and other domestic and wild animals. However, generally those compounds have minimal or non-existant water solubility which renders the compounds non-suitable for injectable administration and other forms of administration which require aqueous solutions. Often where a compound does demonstrate significant aqueous solubility, the solution thus formed is found to be unstable for the period of time necessary to provide for a usuable injectable formulation. The instant invention provides for more novel salts of anthelmintically active compounds, which salts are soluble in an aqueous medium and which produce solutions markedly more stable than prior art solutions.